Additional public health considerations to the INSPQ technical briefing of July 6, 2022 - PowerPoint Presentation

1. Additional public health considerations to the INSPQ technical briefing of July 6, 2022regarding the Horne SmelterSUMMARY SCIENTIFIC EXPERTISEMathieu Valcke, PhD, Specialized Scientific Advisor Gabriela Ponce, MSc, Scientific AdvisorMarie-Hélène Bourgault, MSc, Scientific Advisor Stéphane Perron, MD, MSc, FRCPCAugust 10, 2022

2. PreambleThis presentation was produced on short notice at the request of public health authorities following the publication of the Carcinogenic Risk Assessment of Ambient Air Arsenic and Cadmium concentrations in the city of Rouyn- Noranda.While the authors of the study are confident in its overall findings, further analysis might possibly reveal minor nuances or inaccuracies. Indeed, due to time constraints, the content has not yet been peer reviewed at the time of presentation.A publication is currently in preparation.

3. Initial questions related to the public health authority mandate Until the 3 ng/m3 standard for arsenic is reached, what reference values need to be met to prevent the potential non-carcinogenic effects on fetal and newborn development in the current context?What are the risks of carcinogenic and non- carcinogenic effects associated with these benchmarks?

4. Topics coveredProposed ambient air reference values for arsenic (As), lead (Pb) and cadmium (Cd) needed to protect the population from non- carcinogenic effects.Carcinogenic risk projections for ambient air As, Cd, and nickel (Ni) concentrations in the Notre-Dame district (QND).An integrated perspective on the risk related to the targeted air contaminants.Current risk of non-carcinogenic effects for As, Pb and Cd concentrations in soil (QND and the rest of Rouyn-Noranda).Conclusion

5. Methodology

6. Methodological concepts used in the evaluation of non-carcinogenic riskReference values with threshold:Provides an exposure value to ensure that the population is protected for a given effectRelates to the effect appearing at the lowest exposures and therefore is protective against other effectsDaily or annual exposureExposure Assessment:Ambient air concentrationsDoses by soil ingestionEffect threshold Exceedance?Reference valuesvs.Estimated or measuredexposure

7. Legal station and station 8006School Notre-Dame de ProtectionStation 8049Station 8045Map of Notre-Dame district sampling stations

8. Proposed ambient air reference values for non-carcinogenic effects

9. Arsenic: proposed annual and daily reference valuesAnnual average: 15 ng/m3 (Cal EPA, 2014):Protective value for IQ declineBased on a study of ingestion of drinking water by 10 year-old children in BangladeshDaily maximum: 200 ng/m3 (Cal EPA, 2014):Protective value for developmental effectsBased on an inhalation study in mice; reduction of fetal weight

10. Lead: annual standard and daily reference value Compliance with the annual standard of 100 ng/m3 (prevents blood lead levels associated with a variety of effects, including IQ decline)Daily maximum: 350 ng/m3 (estimated value based on the 2000 WHO approach)- Protective value to prevent reaching the mandatory blood lead reporting threshold of 50 µg/l

11. Cadmium: annual standard and daily reference valueCompliance with the annual standard of 3.6 ng/m3 (carcinogenic effect)Daily maximum: 30 ng/m3 (ATSDR, 2012):Protective value for non-carcinogenic respiratory effectsBased on an inhalation study in rats; respiratory tract inflammation

12. Carcinogenic risk projections in the QND for  As,  Cd  and  Ni  concentrations  in ambient air (various scenarios)

13. Lung cancer risk in the QND for various scenarios of As concentrations reduction towards the standard Risk considered unacceptable:10 in 100,000Suggested acceptable risk for copper smelters in the United States (U.S. Federal Register):3 in 100,000Negligible risk:1 in one million (0.1 in 100,000)Current15 ng/m33 ng/m312.3 per 100,0003.3/100,0002.0 per 100,0003.3 per 100,000

14. Lung cancer risk in the QND for various scenarios of As concentrations reduction towards the standardUsing an average estimate of "unit risk" values by five organizations: U.S. EPA, WHO, CalEPA, Health Canada, TCEQAssumption of the compliance with annual standards for Cd and Ni.The 70-year prospective calculation from 2023 onward shows 2 to 3.5 cases per 100,000 in 10 different sequence scenarios of projected average concentration reduction at station 8006 by 2028 (between 3 and 15 ng/m3)   - As such, carcinogenic risk varies primarily with the projected annual average air concentration of As at station 8006 (2028 and beyond), and not with the 2023–2028 reduction sequence.

15. An “integrated” view of riskThe results suggest that:By the time the As standard of 3 ng/m3 is reached, the annual average ambient air As concentration of 15 ng/m3 at the legal station:Protects against developmental effects on young children (a drop of 1 IQ point); effects beyond this value cannot be excluded.Presumably also prevents the exceedance of the daily 200 ng/m3 reference value for protecting fetal development Corresponds to a carcinogenic risk of slightly more than 3 cases per 100,000* over 70 years, for future generations* If both the standards for Cd and Ni are met.

16. Current risk of non-carcinogenic effects for As, Pb and Cd concentrations in soils (QND and rest of Rouyn-Noranda)

17. Risks of non-carcinogenic effects on young children for As, Pb and Cd concentrations in soils (considering bare soil)Contaminant Sector Average Proportion of 6 month -(targeted exceedance factor 4 year olds witheffect) of the reference exposure greater than value the effect thresholdArsenicQND9.75.4%(-1 IQ pt.)Rest of Rouyn6.81.2%LeadQND0.48.5%(-1 IQ pt. Rest of Rouyn0.47.7%CadmiumQND0.050%(renal effect)Rest of Rouyn0.050%Contaminant(critical effect)SectorAverage exceedance factor  of the reference valueProportion of children aged 6 months – 4 years with exposures above effect threshold 

18. Conclusion and insights to reduce uncertainties

19. ConclusionThis study focused on As, Pb, and Cd because of they account for the major part of the risks associated with Horne smelter emissions.Until the As standard of 3 ng/m3 is reached, a concentration of 15 ng/m3 or less will protect the most vulnerable individuals (including fetuses and infants) from non-carcinogenic effects, provided the following conditions are also met:addition of a maximum 200 ng/m3 daily concentration of Ascompliance with annual standards for Pb, Cd and Niaddition of maximum daily concentrations of 350 ng/m3 for Pb and 30 ng/m3 for Cd.

20. ConclusionAn annual average As concentration of 15 ng/m3 at station 8006 will help to reduce the risk of lung cancer for future QND generations by a factor of about 4 compared to the current situation, at a level considered acceptable in similar North American contexts.Current exposure to arsenic and lead in soils poses a risk of concern for young children. Increased efforts to decontaminate soils to current generic standards would reduce these risks.This evaluation includes uncertainties that are inherent to any risk assessment process:Exposure assessmentEffects of other substances not considered in the analysis

21. Ways to reduce uncertaintiesDaily sampling to better monitor the evolution of As, Pb, Cd, and Ni ambient air concentrations over timeIncreased monitoring of other contaminants with carcinogenic potential: fine particles, antimony, chromiumPb, As and Cd human biomonitoringImproved access to the Horne Smelter’s environmental sampling data

22. Appendix

23. AcronymsAs: arsenicATSDR: Agency for Toxic Substances and Disease RegistryCalEPA: California Environmental Protection AgencyCd : cadmiumNPRI: National Pollutant Release InventoryNi: nickelWHO: World Health OrganizationPb : leadIQ: intelligence quotientQND : Notre-Dame districtTCEQ: Texas Commission on Environmental QualityU.S. EPA: United States Environmental Protection Agency